How to make handlebars keep indentation when replacing a multi-line value? - html

Consider this handlebars template:
<div>
{{content}}
</div>
And the following data:
{
content: 'foo\r\nbar'
}
And the desired result (what I need):
<div>
foo
bar
</div>
But when compiling the handlebars template with the data I get this:
<div>
foo
bar
</div>
So, how to make handlebars keep indentation when replacing a multi-line value?
Of course, changing the data is not an option.

From the compile reference:
preventIndent: By default an indented partial-call causes the output of the whole partial being indented by the same amount. This can lead to unexpected behavior when the partial writes pre-tags. Setting this option to true will disable the auto-indent feature.
So, it follows that if you're able to set up your template so that content is rendered by a partial, e.g.:
<div>
{{> ContentPartial}}
</div>
Then before it's rendered, register the ContentPartial partial:
Handlebars.registerPartial('ContentPartial', '{{content}}')
then it will preserve indentation. (I actually discovered this feature when the auto-indentation screwed up formatting in my <textarea> and I had to disable it).

It's not possible. Handlebars didn't know anything about the place where data will be embedded. You have line break in data and you get line break in result, there is no and nowhere to get a tab (4 spaces) after foo, have just one line break.
One of the ways to deal with your problem is to use such helper, that knows about the indentation and process passed argument proper way.
See quick example.
Helper:
Handlebars.registerHelper('indent', function (data, indent) {
var out = data.replace(/\n/g, '\n' + indent);
return new Handlebars.SafeString(out);
});
used as:
{{indent foo ' '}}
will produce you multiline output with specified indentation.

Adding to #tobias-j answer, the partial can be written inline with no need to register it on the code.
So, your template can be written as:
{{#*inline "inlineContent"}}
{{content}}
{{/inline}}
<div>
{{> inlineContent}}
</div>
You can see it working on the playground.

Related

How to Create an HTML Template?

Problem
I have a collection of images with linked captions on a page. I want them each to have identical HTML.
Typically, i copy and paste the HTML over and over for each item. The problem is, if i want to tweak the HTML, i have to do it for all of them. It's time-consuming, and there's risk of mistakes.
Quick and Dirty Templating
I'd like to write just one copy of the HTML, list the content items as plain text, and on page-render the HTML would get automatically repeated for each content-item.
HTML
<p><img src=IMAGE-URL>
<br>
<a target='_blank' href=LINK-URL>CAPTION</a></p>
Content List
IMAGE-URL, LINK-URL, CAPTION
/data/khang.jpg, https://khangssite.com, Khang Le
/data/sam.jpg, https://samssite.com, Sam Smith
/data/joy.jpg, https://joyssite.com, Joy Jones
/data/sue.jpg, https://suessite.com, Sue Sneed
/data/dog.jpg, https://dogssite.com, Brown Dog
/data/cat.jpg, https://catssite.com, Black Cat
Single Item
Ideally, i could put the plain-text content for a single item anywhere on a page, with some kind of identifier to indicate which HTML template to use (similar to classes with CSS).
TEMPLATE=MyTemplate1, IMAGE-URL=khang.jpg, LINK-URL=https://khangssite.com, CAPTION=Khang Le
Implementation
Templating systems are widely used, like Django and Smarty on the server side, and Mustache on the client side. This question seeks a simple, single-file template solution, without using external libs.
I want to achieve this without a framework, library, etc. I'd like to put the HTML and content-list in the same .html file.
Definitely no database. It should be quick and simple to set it up within a page, without installing or configuring additional services.
Ideally, i'd like to do this without javascript, but that's not a strict requirement. If there's javascript, it should be ignorant of the fieldnames. Ideally, very short and simple. No jquery please.
you mean Template literals (Template strings) ?
const arrData =
[ { img: '/data/khang.jpg', link: 'https://khangssite.com', txt: 'Khang Le' }
, { img: '/data/sam.jpg', link: 'https://samssite.com', txt: 'Sam Smith' }
, { img: '/data/joy.jpg', link: 'https://joyssite.com', txt: 'Joy Jones' }
, { img: '/data/sue.jpg', link: 'https://suessite.com', txt: 'Sue Sneed' }
, { img: '/data/dog.jpg', link: 'https://dogssite.com', txt: 'Brown Dog' }
, { img: '/data/cat.jpg', link: 'https://catssite.com', txt: 'Black Cat' }
]
const myObj = document.querySelector('#my-div')
arrData.forEach(({ img, link, txt }) =>
{
myObj.innerHTML += `
<p>
<img src="${img}">
<br>
<a target='_blank' href="${link}">${txt}</a>
</p>`
});
<div id="my-div"></div>
This answer is a complete solution. It's exciting to edit the HTML template in codepen and watch the layout of each copy change in real time -- similar to the experience of editing a CSS class and watching the live changes.
Here's the code, followed by explanation.
HTML
<span id="template-container"></span>
<div hidden id="template-data">
IMG,, LINK,, CAPTION
https://www.referenseo.com/wp-content/uploads/2019/03/image-attractive.jpg,, khangssite.com,, Khang Le
https://i.redd.it/jeuusd992wd41.jpg,, suessite.com,, Sue Sneed
https://picsum.photos/536/354,, catssite.com,, Black Cat
</div>
<template id="art-template">
<span class="art-item">
<p>
<a href="${LINK}" target="_blank">
<img src="${IMG}" alt="" />
<br>
${CAPTION}
</a>
</p>
</span>
</template>
Javascript
window.onload = function LoadTemplate() {
// get template data.
let sRawData = document.querySelector("#template-data").innerHTML.trim();
// load header and data into arrays
const headersEnd = sRawData.indexOf("\n");
const headers = sRawData.slice(0, headersEnd).split(",,");
const aRows = sRawData.slice(headersEnd).trim().split("\n");
const data = aRows.map((element) => {
return element.split(",,");
});
// grab template and container
const templateHtml = document.querySelector("template").innerHTML;
const container = document.querySelector("#template-container");
// make html for each record
data.forEach((row) => {
let workingCopy = templateHtml;
// load current record into template
headers.forEach((header, column) => {
let value = row[column].trim();
let placeholder = `\$\{${header.trim()}\}`;
workingCopy = workingCopy.replaceAll(placeholder, value);
});
// append template to page, and loop to next record
container.innerHTML += workingCopy;
});
};
New version on github:
https://github.com/johnaweiss/HTML-Micro-Templating
Requirement
As specified in the question, this solution is intended to optimize the coding experience on the HTML side. That's the whole point of any web templating. Therefore, the JS has to work a little harder to make life easier for the HTML programmer.
The question seeks a reusable solution. Therefore, JS should be ignorant of the template, fields, and data-list. So unlike #MisterJojo's answer, the template and all data are in my HTML, not javascript. The JS code is generic.
Design
My solution is based on the <template> tag, which is intended for precisely this usage. It has various advantages, like the template isn't displayed, processed, or validated by the browser, so it has less impact on performance. Programmer doesn't have to write an explicit display:none style.
https://news.ycombinator.com/item?id=33089975
However, <template> tags are normally only intended for loading content into the layout. That's inadequate. This tool allows template variables anywhere in the HTML, including inside the tags (eg attributes like <img src).
HTML
My HTML has three blocks:
template: The HTML coder develops their desired display-structure of the output, in real HTML (not plain text). Uses <template>
data: The list of records each of which should be rendered using the same template. Uses <span> with a HIDDEN attribute.
container: The place to display all the output blocks. Uses <span>.
Template
My sample template includes 3 placeholders for data:
${LINK}
${IMG}
${CAPTION}
But of course you can use any placeholders, any number of them. I use string-literal delimiting-style (although i'm not actually using them as string-literals -- i just borrowed the delimiter style.)
Data Element
The question specifies data should be stored in HTML. It should require minimal keystrokes.
I didn't want to redundantly retype the fieldnames on every row. I didn't use slotting, JSO, Jason, or XML syntax, because those are all verbose.
https://developer.mozilla.org/en-US/docs/Web/Web_Components/Using_templates_and_slots
It's a simple delimited list. I eliminated all braces, brackets, equals, parens, colons etc.
I put the fieldname-headers only on the first row. The headers are a visual aid for the HTML developer, and a key for Javascript to know the fieldnames and order.
Record Delimiter: End-of-line
Field Delimiter: Double-commas. Seems safe, and they're easy to type. I don't expect to see double-commas in any actual data. Beware, the developer must enter a space for any empty cells, to prevent unintended double-commas. The programmer can easily use a different delimiter if they prefer, as long as they update the Javascript. You can use single-commas if you're sure there will be no embedded commas within a cell.
The data block is hidden using the hidden attribute. No CSS needed.
It's a span to ensure it takes up no room on the page.
JAVASCRIPT
Data
The data is processed by Javascript with two split statements, first on newline delimiter, then on the double-comma delimiter. That puts the whole thing into a 2D array. My JS uses trims to get rid of extra whitespace as needed.
Place-holder Substitution
Handling multiple entries requires plugging each entry into the template.
i went with simple string-replacement instead of string literals.
Multiple Templates
New version which supports multiple templates, and ability to use same template in multiple locations on same page.
https://github.com/johnaweiss/HTML-Micro-Templating
Future
Inspired by #MisterJojo, an earlier version of my solution used template literals to do the substitution. However, that was a bit more complicated and verbose, and seemed to require use of eval. So i switched to .replaceAll. Yet template-literals seems like a more appropriate method for templates, so maybe i'll revisit that.
A future version may adapt to whatever custom field-delimiter the HTML developer uses for the data block.
The dollar-curly delimiter for placeholders is a bit awkward to type. So i'm interested in finding a less awkward non-alpha delimiter that won't conflict with HTML. Considering double-brackets or braces [[NAME]]
Maybe there are simpler ways to pull the data-table into JS.
I've read components work well with <template>, but i didn't go there.
Imo, the JS committee should develop a variable-placeholder feature for <template> tags, and natively accommodate storing the data in HTML. It would be great if something like this solution was part of the rendering engine.

Have different style apply to different syntax highlighter languages

I have a jekyll site where I post a lot of shell examples in code blocks. I struggle to visually delineate between the script/shell commands and their output of the commmands.
Generated html:
<pre><code class="language-powershell">
function DemoCode {
return 'rab', 'oof'
}
DemoCode
rab
oof
</code></pre>
In this example, the last two lines need to be obviously the output from the first 4 lines.
Markdown is currently just normal triple-backtick with a powershell tag:
```powershell
function DemoCode {
return 'rab', 'oof'
}
DemoCode
rab
oof
```
I'd prefer to avoid splitting it into a second code block. Wordpress let me do this with inline style tags, but it was a pig of a job.
This isn't a good solution for me but I could have a separate code block with the 'plaintext' tag to the syntax highlighter:
The best I have so far is indeed with separate code blocks. If I apply the 'plaintext' tag to rouge, then at least I don't get syntax highlighting, which helps. But the generated html still inherits the same CSS from .highlight.
Markdown:
```powershell
function Write-Stuff {
Write-Output $Stuff
}
```
```plaintext
Output I would like with different color and background-color
```
I still need that to inherit different CSS, though. Generated HTML:
<div class="language-powershell highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="c1">#this is formatted with md code block and powershell tag</span>
</code></pre></div></div>
<div class="language-plaintext highlighter-rouge"><div class="highlight"><pre class="highlight"><code>#formatted with md code block and plaintext tag
</code></pre></div></div>
If you want to go with separate code blocks, you can use a block IAL to set a custom class on the syntax highlighted blocks:
{:.my-custom-class}
``` powershell
function Write-Stuff {
Write-Output $Stuff
}
```
This would insert the my-custom-class right next to language-powershell highlighter-rouge, allowing you to customize your CSS appropriately.
As for avoiding splitting the block: That is not possible with kramdown. However, you could implement a custom syntax highlighter that knows how to do this.

Meteor {{#markdown}}

I am making a forum with markdown support.
I've been using meteor's markdown parser {{#markdown}} and have found something disturbing that I can't seem to figure out.
I am using {{#markdown}}{{content}}{{/markdown}} to render the content inserted into database.
The disturbing thing, for example, if someone writes up html without inserting it into the code block in the content...
example
<div class = "col-md-12">
Content Here
</div>
This will render as a column. They could also make buttons and etc through writing the HTML for it.
How to disable this behaviour so that when HTML is written it will not render into HTML but just simply show it as text?
You can write global helper, which will strip all html tags:
function stripHTML(string){
s = string.replace(/(<([^>]+)>)/ig, '');
return s;
}
Template.registerHelper('stripHTML', stripHTML)
Usage :
{{#markdown}}{{stripHTML content}}{{/markdown}}
Test it in console:
stripHTML("<div>Inside dive</div> Text outside")

How can I eliminate the empty line in code blocks rendered by jekyll?

GitHub Pages Jekyll use Pygments by default to render syntax highlighting for code blocks. But I prefer an easier alternative highlight.js to do the job because I only need to indent 4 spaces to mark code blocks in the markdown source files.
However, my R code are all mistakenly interpreted as php or perl or makefile or other type of code by highlight.js, and I want to manually mark the code block by
```r
(some r code)
```
instead. But when I use this, the first line of the code block always appears to be a blank line. I view the HTML source code produced by the 4-space mark, it is like
<pre><code>x <- rnorm(100)
y <- 2*x + rnorm(100)
lm(formula=y~x)
</code></pre>
which does not suffer from this problem.
How can I eliminate the blank line in the first line of the code block?
I face the same issue today when I change my highlighter to highlight.js.
With the help from others, I finally git rid of this blank line, and willing to share the solution. Basically, the whitespace inside <pre> is not trimmed, and be treated as a newline in the rendered page (you can use firebug extension of Firefox enabled with show whitespace to observe the extra line).
Then the solution is obvious.
put pre and code tags at the same line with your actual code. like this:
<pre><code class="css">#font-face {
font-family: Chunkfive; src: url('Chunkfive.otf');
}
or using solution provided by mhulse to make your raw post more readable
<pre><code
>line of code
Here and ...
Here
</code></pre>
Write your own js code to trim L/R whitespace(s) of your content before it be put in <pre>
For more details, check this page.

Extra whitespace in HTML values rendered with Jade

Every time I write my HTML in Jade, I am getting extra whitespace added after each element's value.
For example, I will have a line like this in my Jade Template:
label(for="keyword") Keyword
And when it's rendered, the source will look like this:
<label for="keyword_1">Keyword
</label>
Ran into some problems with that extra whitespace messing w/ my CSS. Plus, it just doesn't look as tidy :)
Anyone know how I can prevent it from being inserted?
Check the update at the bottom
I assume you're using express - check your app settings.
app.set('view options', { pretty: false })
If you have jade rendering in pretty mode (pretty: true) then it will arrange your generated source (tags) with nested indention. Turning pretty printing off should resolve your problem (though make sure you don't have trailing space, as pointed out by #alessioalex).
If you have a reason requiring you to output pretty formatting (client spec, in my case) then you can try some other things. I had a similar issue with occurring with the textarea tag; frustrating because the whitespace is actually injected into the content of the form. The way I got around this was to embed a the literal html with the closing tag:
<textarea name="someField"></textarea>
The docs can give you some more details (search for html in this case). There is open issue #341 on github which suggests an approach like this one for scalate, but it doesn't currently work in jade (as of version 0.19.0) .
HTH
Update
Ok - subtle and cool... there is a better way to keep the sexy output from pretty: true and avoid spacing inside of a tag (my textarea example)... I just tried appending a . to the end of the tag (see code) and it Just Worked™ :-)
form(name='frmname', method='POST')
textarea(name='someField').
Renders:
<form name="frmname" method="POST">
<textarea name="someField"></textarea>
</form>
Beauty!
Why does this work? Because jade treats the . suffix on the tag as an indicator that the tag will contain a text block (only), and then no text block is provided, so it defaults to '', an empty string.